The present invention relates to structures for control of shoreline erosion, and in particular to structures that include a fabric or other membrane used to filter suspended sand and sediment.
A variety of structures have been used in an attempt to ameliorate or control the erosion of shoreline along the coasts of both freshwater lakes and oceans. Depending upon the prevailing currents or wave patterns along a given section of coast, certain structures may prove more effective than others in one area yet less effective in other areas. Although many different structures have been adapted for different erosion conditions, heretofore a large number of erosion control devices have provided rigid structures that can actually be counterproductive to controlling erosion over the long term or have the effect of merely shifting the erosion to another location. For example, rigid seawalls, groins or pylons provide solid barriers to normal currents and wave action. When water which is moving toward the shore strikes the rigid barrier it is either deflected downwardly against the sea bottom or laterally along the wall. This action causes the seabed to be subjected to a focused or accelerated erosion in that region since the eroding effect of the moving water is not dissipated over a wider area.
Further, the presence of rigid barriers, whether extending up out of the water or submerged, can reduce the field of use for the shoreline being protected. These rigid structures can pose a danger of injury to swimmers who may accidentally strike the barrier, as well as posing a similar impediment to boating and fishing. Further, rigid barriers extending above the water's surface dramatically detract from a coastline's natural beauty.
Other types of erosion control structures have used various fabrics which are placed on the embankment in order to hold the underlying sand in place and prevent the sand from being washed out away from the shoreline. Merely holding existing sand in place, however, does not aid in preventing erosion from areas that are not actually covered by such fabric.